Antineutrophil cytoplasmic antibody-associated vasculitis complicated by subarachnoid hemorrhage: A case report and literature review

RATIONALE: antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is an autoimmune syndrome characterized by necrotizing inflammation of small-to medium-sized vessels accompanied by the presence of peripheral blood ANCA. Subarachnoid hemorrhage (SAH) is an uncommon complication of AAV. The purpose of this report is to present a rare case of AAV complicated by SAH and to review the existing literature, thereby enhancing awareness of this severe neurological manifestation and its management strategies. PATIENT CONCERNS: We report the case of a 56-year-old male who presented with cough, blood-tinged sputum, proteinuria, elevated serum creatinine levels, and headache. Laboratory examinations confirmed the presence of anti-myeloperoxidaseantibody, imaging revealed SAH, and angiography identified a ruptured anterior communicating artery aneurysm. DIAGNOSES: The final diagnosis was AAV complicated by SAH. INTERVENTIONS: The patient underwent prompt endovascular coiling, with concurrent immunosuppression using methylprednisolone and intravenous cyclophosphamide. OUTCOMES: Following endovascular coiling, the patient's subarachnoid hemorrhage and associated neurological symptoms (headache, dizziness) resolved completely. Immunosuppressive therapy led to the resolution of respiratory symptoms (cough and blood-tinged sputum), the clearance of hematuria, and a significant reduction in inflammatory markers, such as C-reactive protein (CRP) and erythrocyte sedimentation rate. However, despite immunosuppressive treatment, with serum creatinine levels fluctuating between 320 and 450 μmol/L, and heavy proteinuria (e.g., 24-hour urine protein of 3360.21mg) persisted. Additionally, the patient developed deep vein thrombosis 1 month after discharge, which was successfully managed with anticoagulation therapy and the placement of an inferior vena cava filter. LESSONS: SAH is a rare but life-threatening complication of AAV. Vigilance for acute neurological symptoms, such as headache, enables early intervention. Combined endovascular repair for SAH and immunosuppressive therapy significantly improve outcomes.